The present invention relates to a tape carrier package for semiconductor devices and a liquid crystal module using the tape carrier package.
Conventionally, a liquid crystal driver comprising an IC or the like for driving a liquid crystal panel is, in many cases, mounted on a liquid crystal panel in the form of TCP (Tape Carrier Package), which is a form of package for semiconductor devices. FIG. 9 shows an example of such a liquid crystal panel module on which semiconductor devices are mounted.
As shown in FIG. 9, a liquid crystal panel 101 is connected to flexible boards 103, 104 by a plurality of TCPs 102, 102, . . . and each TCP 102 is equipped with a liquid crystal driver chip 105. The TCP 102 is supplied with power supply for driving the liquid crystal driver chips 105 as well as various control signals from the flexible boards 103, 104, and supplies the liquid crystal panel 101 with a voltage for driving the liquid crystal panel 101.
Next, FIG. 10 shows an example of the conventional TCP. As shown in FIG. 10, the TCP has output-side lines 201 and input-side lines 202. These output-side lines 201 and input-side lines 202 are formed on a base material 203. This base material 203 has a device hole 205 formed generally in the center. This device hole 205 makes exposed inner end portions 201A of the output-side lines 201 and inner end portions 202A of the input-side lines 202. Then, a semiconductor chip (not shown) is mounted onto this device hole 205, and bump electrodes of this semiconductor chip are connected to the inner end portions 201A of the output-side lines 201 and the inner end portions 202A of the input-side lines 202. Also, outer end portions 201B of the output-side lines 201 are connected to the liquid crystal panel. Outer end portions 202B of the input-side lines 202, on the other hand, are exposed by an input connection slit 207 formed in the base material 203, and these outer end portions 202B are connected to the wiring on the flexible board. Through this wiring on the flexible board, the TCP performs exchange of power supply for driving the liquid crystal panel, power supply for driving semiconductor, and various control signals.
In this connection, in recent years, because of the demands for lighter, thinner, shorter and smaller products from the market, downsizing is indispensable also for semiconductor devices to be mounted on a liquid crystal panel. As a response to such a demand, there has been proposed a technique for multilayer interconnection for TCPs. In this regard, for example, Japanese Patent Laid-Open Publications SHO 64-19737 and HEI 6-29352 can be mentioned.
That is, currently, a flexible board equipped with liquid crystal panel driving power supply, semiconductor device driving power supply and various control signal lines leading to semiconductor devices is provided as a multilayer board of, for example, five layers. Therefore, by forming the TCP, which is to be connected to the flexible board, into a multilayer interconnection structure, the flexible board can be reduced in wiring burden and, as a result, downsized.
Further, forming the TCP into a multilayer interconnection structure increases the degree of freedom of wiring, so that even when replacement of a liquid crystal driving semiconductor device with a new liquid crystal driving semiconductor device having a different form of input terminals is involved, the flexible board can be commonized by changing the interconnections within the TCP. Thus, a cost reduction can be achieved.
Still further, whereas the liquid crystal panel driving power supply to be fed to the liquid crystal driving semiconductor device is fed to the semiconductor device generally via a plurality of bumps (pads), supply lines for this power supply, when implemented by multilayer interconnection on the TCP, make it possible to lower the resistance, to prevent voltage drops, and to increase the noise immunity.
However, as compared with the monolayer interconnection TCP, the multilayer interconnection TCP decreases in throughput as the man-hours of manufacturing processes or the complexity increases, and moreover the material itself increases. As a result of this, the cost per unit area of the TCP becomes at least a double or more. On these accounts, the multilayer interconnection TCP has been kept from positive adoption, as it stands.
However, recent years' trends toward lighter, thinner, shorter and smaller products as well as toward reduction in cost could not be met when the TCP on which semiconductor devices are mounted is discussed singly. That is, there is a need for comprehensive discussions that are directed also to flexible boards to be connected to the TCP, while there is a strong demand for multilayer interconnections of TCPs.
Therefore, an object of the present invention is to provide a low-cost tape carrier package of multilayer interconnection structure as well as a liquid crystal module using the tape carrier package.
In order to achieve the above object, there is provided a tape carrier package on which a semiconductor device is to be mounted, comprising:
a base material 3; wiring lines 7, 15 formed on the base material 3; and an insulating top coat 35 for insulating and protecting the wiring lines, wherein
the wiring lines 7, 15 have a plurality of line exposed portions A-J, a-j exposed from the insulating top coat 35, and
at least one pair of line exposed portions A, a . . . , which are opposed to each other by bending the base material 3 along a bending portion 11 formed in the base material 3, are electrically connected to each other.
In this constitution of the invention, the base material is bent along the bending portion, by which opposed line exposed portions are electrically connected to each other. As a result, a two-layer interconnection structure of three-dimensional interconnection can be realized. This three-dimensional interconnection structure can be achieved by bending the base material, and therefore low in cost.
In an embodiment of the present invention, the one pair of line exposed portions A, a are electrically connected to each other by an anisotropic conductive film 37.
In this embodiment of the invention, line exposed portions of upper-layer interconnections and line exposed portions of lower-layer interconnections can be electrically connected to each other by an anisotropic conductive film.
In an embodiment of the present invention, bending alignment marks 17, 18 used in bending the base material 3 are formed in the base material 3.
In this embodiment of the invention, the base material can be bent so that a pair of line exposed portions that should be electrically connected to each other are accurately opposed to each other, with the use of the bending alignment marks.
In an embodiment of the present invention, the bending portion 42, 43 is provided so that, relative to main lines 7 connected directly to the semiconductor device, the bending portion 42, 43 extends in adjacency to a direction in which the main lines 7 are arrayed and along a direction in which the main lines 7 extend.
In this embodiment of the invention, since the bending portion is in adjacency to the direction in which the main lines are arrayed, the size in the direction in which the main lines extend before bending at the bending portion can be reduced, as compared with the case in which the bending portion is adjacent to the direction in which the main lines extend.
In an embodiment of the present invention, an input-connection slit 10 by which the main lines 7 connected directly to the semiconductor device are exposed are formed in the base material 3, and
an input-connection hole 12 which is to be laid on the input-connection slit 10 when the base material 3 is bent 180.degree. along the bending portion 11 is formed in the base material 3.
In this embodiment of the invention, even after the tape carrier package has been bent, the main lines remain exposed upward and downward at the input-connection hole and the input-connection slit. Therefore, even after the bending, the exposed portions of the main lines can be connected to the flexible board from both above and below.
Also, there is provided a liquid crystal module which uses the tape carrier package as mentioned above.
This liquid crystal module of the invention employs a low-cost tape carrier package having a three-dimensional interconnection structure. Therefore, the liquid crystal module can be downsized and reduced in cost.